So, as someone who had similar fears about jumping into arena, finally did, and hit challenger, I will tell you this: you should not be comparing yourself to players who have been doing this for 5-10+ years. That will absolutely increase your anxiety. Its a playstyle to strive for, but don’t be looking twenty miles down the road when you really need to be looking at the new few steps ahead of you. Walking a few steps a time is how you eventually get down the road.
You need to be focused on improving at the basics. Openers, set ups, positioning, seeing the whole arena, that sort of thing. And if you mess up and people flame you for it, they’re sorry. They’ve messed up too, I guarantee it.
Arena is very, very much crawl > walk > run > sprint. Don’t pressure yourself to sprint before you’ve got crawling down.
Good luck and most importantly, have fun.
Edit: Arena is not going to be the only way to get high level gear. It will probably be the hardest. If that’s your main concern and you don’t really love pvp, it might not be worth it for you.